DESCRIPTION: This project comprises a broad-based investigation into visual object and surface perception. Much of human thought and behavior is organized around the perception and representation of objects. Among the fundamental, unsolved problems of object perception is unit formation: How do we obtain descriptions of connected objects in the three-dimensional world despite interruptions - across space and time-of their contours and surfaces in their projections to the eyes? Answering these questions of unit formation and related aspects of object perception is the goal of the research. Psychophysical experiments using objective performance tasks with normal, human adult observers are used to probe the information (stimulus relationships) involved, the representations formed and the processing characteristics of human object perception. The data are used to construct geometric and information-processing models of the contour and surface relationships that lead to perception of connected objects, as well as to inform models of the neural activity underlying perception. Building on prior work, the current project extends the empirical and theoretical efforts into the less well-studied domains of three-dimensional relationships in object formation and dynamic (motion-carried) information. Particularly exciting is the suggestion in recent work that common principles may describe unit formation in two and three dimensions, and dynamic vision. These efforts will lead toward a better understanding of fundamental cognitive and behavioral processes - those that achieve representations of objects, surfaces and scenes. The results will have manifold implications for understanding normal and impaired human function, for constructing artificial (including robotic) vision systems for probing the neural mechanisms of perception.